Settings shell plugin: a pure composition face. It occupies sidebar.settings with the trigger chrome and modal settings panel, and declares the slots registrants fill: settings.trigger / settings.header / settings.close (chrome content), settings.section (one page per feature), and settings.onboarding (ordered feature-owned steps on the empty Hero). The shell ships no copy and reads no locale state — all text arrives from registrants (ui-settings-general owns chrome, General, and the product welcome step; features own their sections, rows, and conditional onboarding steps).

The shell projects the onboarding ledger into ascending order and mounts exactly one step at a time. The active registrant receives its id, complete(), and an openSection(id) callback; completing or skipping transfers ownership to the next entry. Registrants own durable completion, capability readiness, copy, and mutations, so two independently registered dialogs cannot stack and the shell does not become a second configuration fact source.

Model Experience

None, as the settings shell serves browser UI composition; nothing here reaches a model request.

KV Cache effect

None; this package neither assembles nor sends a provider request.

Known Limitations and Deferred Work

Panel is browser-preference scope only — host-side settings surfaces (permission mode, tool-call mode) have no RPC backing yet; their skeletons live in ui-settings-general.